If the carriers had been hit, as planned, how would that have changed the war? Hawaii would have been abandoned as untenable. Japanese attacks on the mainland might have followed. We would not have surrendered Hawaii without a fight, in other words, we would have geared up to return and take back the islands. Japan would have lacked the military strength to obtain permanent hold over the west coast, so would not have done more than probe and strike here and there, hoping for a moral victory (collapse of US morale). It would not have come. We would have thrown literally everything into defeating Japan as thoroughly as possible.

That would have altered our participation in Europe enormously. It would have delayed that intervention. It would have reduced our support of Russian fighting capacity, and by delaying that, would have delayed Hitler's defeat indefinitely.

The Japanese had no intention of taking Hawaii, getting the carriers would have made their conquest of the Pacific they had already planned go more smoothly. That is about it, things from 1943 onward would be pretty much the same with a different starting point (not Hawaii, but not Guadalcanal either)

So by '43 we'd have had more carriers deployed in the Pacific than the Japanese. The war would possibly have gone on for a few more years beyond '45. Then the European theater would also have gone longer. But essentially no difference in outcome.

In other words, no matter how you cut it, the Japanese high command was guilty of hubris on a huge scale. Leading one to wonder how that mindset is possible to develop so thoroughly. If the outcome was inevitable, it means that to attack at all would bring on disaster for Japan. So the reigning mindset simply did not fathom the American way of thinking….

The Japanese decision to go to war was IMO fundamentally driven by Roosevelt's extremely aggressive and antagonistic foreign policy toward them and was rationalized by (a) Japan's experience in having defeated imperial Russia in 1905, and (b) a poor grasp of the true nature and potentials of the USA by the Japanese political leadership. War with the USA was not unanimously supported within the Japanese military (see Yamamoto's prophetic warning to his superiors for example).

It's interesting to speculate as to the outcome in Europe if the US had concentrated on Japan first and victory in the Pacific taking a year or two longer to achieve. Would for example, Stalin have taken all of Germany, and maybe even more territory further West if the US military isn't there and D-Day isn't launched in 1944?

Yes, Europe would have been radically different in outcome without the US joining when it did. It is not unrealistic to assume the USSR takes over Europe or all of the eastern parts anyway. A deadlocked "eastern front" kind of conflict would possibly have been "unlocked" by eventual US intervention. But the political map of Europe would have been "cold war" to the max right off the bat at the end of the war with Germany.

Where and when would the "Bomb" have been used? Surely that pair of events would have happened differently.

@Weasel: I think that Pearl Harbor (attacking the US) was a terrible mistake. "Better option" would have been to remain on their side of the Pacific and consolidate their gains in China and Indo-China. And resort to diplomacy with the US to buy time. Without direct provocation, it might have been years before the US entered the war, and possibly not at all! The "lend-lease" aid and other material aid to Russia, etc., would have increased, probably bringing the Nazi problem to a stalemate and a negotiated peace and drawing of borders along that stalled out "front". The USSR would have been greatly bolstered by their gains. The world as we know it would not exist.

But, if the Japanese high command is inevitably committed to attacking the US, Pearl Harbor might as well be it. The chance to make an effective strategic hit is only there….

No matter what the outcome of the Pearl Harbor attack, the Japanese never had the capability of seriously attacking the west coast. Only a month after Pearl Harbor the US had eight fully operational battleships based in California. Land based air power and dozens of Army divisions on call. Most of the Japanese invasions in the Pacific were division-sized or smaller. They simply didn't have the logistical capacity for anything so ambitious.

ScottWashburn-Agreed and they had quite a lot of stuff going on at the other side of the Pacific starting around the Pearl Harbor attack time period. That was a large expanse of water to take care of so going further east towards the US mainland or even trying to take and hold Hawaii would have been a bit of a mouthful to chew.

I wonder what would have happened if the Japanese had declared war on the Dutch and invaded Indonesia only? Would the British have declared war with Japan when they were clearly unable to fight another major power, would the US actually committed themselves to war over Indonesia? The capture of the oilfields on Borneo would have solved the Japanese fuel problems and given them trade material when they needed that kind of leverage the most.

"I wonder what would have happened if the Japanese had declared war on the Dutch and invaded Indonesia only?"

Not an expert but did stay at one of those motels in the TV commercial…

I believe a conflict between the US & Japan was more of a "when" not "if" type of a thing. The US had started to rearm and had lots of stuff in the pipeline. I think that if Japan had gone down the Indonesia only path, they would have only delayed the inevitable. Conventional wisdom says that they were assuming a major hit at Pearl Harbor would cause the US population/govt. to seek an avenue towards peace. It actually had a lightening rod effect and "the sleeping giant was awoken."

I seems to me that the most likely reason for Japan attacking the U. S. at all was a failure on the part of their diplomatic corps to grasp the realities of American domestic politics. On the 6th of December public and legislative opinion were widely separated. If the Japanese had struck south into Indo-China, Malaya and the Netherlands East Indies without touching the Phillipines, the American government would have been powerless to employ anything more than harsh language in response. On the 8th of December things were completely different.

Roosevelt drove Japan to war through a succession of punitive economic measures designed to force a Japanese withdrawal from the Chinese mainland. IIRC, an embargo on the export of steel came first, followed by a cut-off of US oil and then a freeze of all Japanese assets in the USA. The oil embargo was especially injurious to the Japanese economy. These US measures did succeed in forcing Japan to act, just not in the manner anticipated.

One can speculate as to whether Roosevelt was inspired by purely noble, humanitarian and altruistic considerations or was perhaps driven by a desire to prevent establishment of the Japanese "Greater East Asia Co-Prosperity Sphere", which would have interfered with, competed against and perhaps overthrown existing US economic interests in Asia.

Blutarski, your entire post places the US as an aggressive force and the poor Japanese as some kind of passive, gentle giant. "drove Japan to war ", "The oil embargo was especially injurious to the Japanese economy", "forcing Japan to act" all make it sound like the Japanese army was out picking daisies while the US ruined their lives. In fact, the Japanese started the war with China, they tried to start a war with the USSR, they started a war with the USA, UK, Netherlands and Australia. The Japanese also behaved horribly to the civilians in conquered territory and their "Greater East Asia Co-Prosperity Sphere" would have only benefited the Japanese. The truth is that the Japanese were solely and wholely responsible for the war in the Pacific.

Beg to disagree. I am not excusing the Japanese for anything. I am simply pointing out -

(a) that Roosevelt undertook very aggressive measures, to the extent of collapsing the Japanese economy, to force them to alter their program of expansionism on the Asian mainland.

(b) that Roosevelt was not necessarily doing so for altogether purely selfless and noble humanitarian reasons.

Japan was hardly the only nation interested in exploiting a weak China for its own economic benefit. In fact, Japan's policy of expansionism onto the Asian mainland went back nearly 1,000 years. But, in 20th century terms, Japan was a decided latecomer to the Chinese feeding trough and the West was not interested in making any room for them.

The arrogant, dismissive and exclusionary policies of the Western nations toward Japan in the early 20th century, starting as early as the Treaty of Portsmouth in 1905 but most certainly manifested in the Treaty of Versailles, directly contributed to the rise of Japanese militarism between the wars. Did Japan start the war in the Pacific? Technically, yes. But the Western nations helped to create the monster. There were no "clean hands" in this sad story.